KR100517104B1 - Non-destructive diagnostic method and non-destructive diagnostic apparatus - Google Patents

Abstract

It is an object of the present invention to diagnose non-destructive diagnosis of the weight loss rate of an insulating member or lubricating oil without stopping the operation of the equipment.

A non-destructive diagnostic method using an optical fiber probe type sensor with light transmission loss or reflected absorbance difference as a parameter is the subject of the present invention.

Description

NON-DESTRUCTIVE DIAGNOSTIC METHOD AND NON-DESTRUCTIVE DIAGNOSTIC APPARATUS}

The present invention provides a non-destructive diagnostic method and a non-destructive diagnostic device capable of diagnosing the weight loss rate of insulating materials, structural materials, lubricating oils, and the like used in the equipment by optically nondestructive regardless of liquids or solids, without stopping the operation of the equipment in operation. It is about.

As a non-destructive diagnostic method for evaluating the degree of deterioration of an insulating material of a rotating machine, as disclosed in Japanese Patent Application Laid-Open No. 64-84162, irradiated light guided to an optical fiber from a white standard light source is composed of the same material as the insulating material. A diagnostic apparatus has been proposed in which the reflected light is reflected by a sensor unit to detect the reflected light through a light receiving optical fiber and performs color calculation by chromaticity or chromaticity difference based on the L * a * b * color system. Here, L * denotes brightness by brightness index, a * and b * are called chromatic index, and indicate chromaticity (color and saturation).

In the conventional art, it is necessary to embed the irradiation optical fiber, the light receiving optical fiber, and the sensor unit in the insulating layer of the device at the time of manufacturing a device such as a rotating machine, so that they can be applied to existing devices that are not embedded therein. There was an inherent problem of not being able to.

The prior art has not been able to diagnose the rate of weight loss of materials.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, and to achieve a non-destructive optical diagnosis of the weight reduction rate of the insulating material or the structural material used in the device without particularly stopping the operation of the device in operation. A diagnostic method and a non-destructive diagnostic device are provided.

The present inventors have examined the relationship between the thermal weight reduction of resins and oils and the optical properties, and as a result, the non-destructive diagnosis can accurately determine the weight loss rate from the change in the surface reflected light intensity or transmitted light intensity of the resin or oil accompanying thermal degradation. A method and a non-destructive diagnostic device have been found to reach the present invention. That is, the gist of the present invention is as follows.

(1) The irradiation light from at least two kinds of monochromatic light sources having different wavelengths is guided to the surface of the measurement object by irradiating the optical fiber for irradiation, and the reflected light from the surface of the measurement object is guided to the light receiver using a light receiving optical fiber. By calculating the reflected absorbance A _λ at each wavelength from the output from the light receiver by Equation 1, the reflected absorbance difference ΔA _λ between the wavelengths is calculated by Equation 2, and stored in advance. A non-destructive diagnostic method characterized by determining the weight reduction rate of a workpiece by comparing and calculating the relationship between the weight loss ratio of the measured workpiece and the reflected absorbance difference between wavelengths.

(Reflectance of the measured object at wavelength λ (nm) is R _λ (%))

(2) at least two kinds of monochromatic light sources having different wavelengths, an optical coupler for guiding the light source light to an irradiation optical fiber, an irradiation optical fiber for irradiating the light source light to the measurement object surface, and reflected light from the surface of the measurement object A light-receiving optical fiber which receives the light and guides the light to the light receiver, a light receiver capable of detecting the intensity of the reflected light at each wavelength and outputting the measured value as an electrical signal externally, and the reflected absorbance at each wavelength from the output value from the light receiver. After calculating (A _λ ) by the equation (1), the reflection absorbance difference (ΔA _λ ) between each wavelength is calculated by the equation (2), and the relationship between the weight loss rate of the measured object stored in advance and the reflection absorbance difference between each wavelength is calculated. A non-destructive diagnostic device comprising a data processing unit for determining a weight reduction rate of a workpiece by performing a comparative operation.

<Equation 1>

A _λ = -log (R _λ / 100)

<Equation 2>

ΔA _λ = A _λ1 -A _λ2 (λ1 <λ2)

(Reflectance of the measured object at wavelength λ (nm) is R _λ (%))

(3) A light receiving optical fiber in which irradiated light from at least one type of monochromatic light source is guided to an irradiation optical fiber, irradiated to a measurement material having a thickness of l (mm), and provided with the transmitted light from the measurement object facing each other. The light transmission loss (L _λ , dB / mm) from the output from the light receiver by the data processing unit, and the weight loss rate and the light transmission loss The non-destructive diagnostic method characterized by determining the weight reduction rate of a workpiece by comparing and calculating the relationship between

(The absorbance of the measurement object at wavelength λ (nm) is A _λ )

(4) at least one type of monochromatic light source, an irradiating optical fiber for irradiating the light source light with a measuring object having a thickness of l (mm), and receiving light that is arranged to face the light transmitted from the measuring object to guide the light receiver; The optical transmission loss (L _λ , dB / mm) is calculated from the output value from the optical fiber, the light receiver capable of detecting the intensity of the transmitted light and outputting the measured value externally as an electric signal, And a data processing unit for determining the weight reduction rate of the measurement object by comparing and calculating the relationship between the weight reduction rate of the measurement object and the light transmission loss stored in advance.

<Equation 3>

L _λ = (10 / l) × A _λ

(The absorbance of the measurement object at wavelength λ (nm) is A _λ )

(5) The irradiation light from at least two kinds of monochromatic light sources having different wavelengths is guided to the surface of the measurement object by irradiating the optical fiber for irradiation, and the reflected light from the surface of the measurement object is guided to the light receiver using a light receiving optical fiber. And comparing the relationship between the weight reduction rate of the workpiece measured in advance by the data processing unit and the reflected absorbance difference between the respective wavelengths to determine the weight reduction ratio of the workpiece.

(6) A light receiver having a spectrometer using a light optical fiber for receiving light from a halogen lamp for irradiating white continuous light to guide the irradiated optical fiber to irradiate the surface of the measurement object, and reflecting light from the surface of the measurement object using a light receiving optical fiber A non-destructive diagnostic method for determining a weight loss rate of a workpiece by inducing a difference between the weight loss ratio of the workpiece and the reflection absorbance difference between the wavelengths.

(7) from at least two types of monochromatic light sources having different wavelengths, an optical coupler for guiding the light source light to an optical fiber for irradiation, an optical fiber for irradiation to irradiate the light source light to the surface of the measurement object, and the surface of the measurement object A light-receiving optical fiber which receives the reflected light and guides the light to a light receiver, a light-receiver capable of detecting the reflection intensity at each wavelength and outputting the measured value as an electric signal externally, at each wavelength from the output value from the light-receiver And a data processing unit for determining the weight reduction rate of the measurement object by comparing and calculating the weight reduction rate of the measurement object in which the reflected absorbance of the light is previously stored.

(8) receiving a light source of a halogen lamp for irradiating white continuous light, an irradiating optical fiber for irradiating the surface of the light source with the light source and a reflected light from the surface of the measured object, and guiding it to a light receiver having a spectroscope An optical fiber for receiving light, a light receiver capable of detecting the reflected light intensity at each wavelength spectroscopically measured by the spectroscope, and outputting the measured value as an electric signal externally, and the difference in the reflected absorbance at each wavelength from the output value from the light receiver; A non-destructive diagnostic device, characterized in that the weight loss rate of the workpiece is determined by comparing the relationship with the weight loss rate of the workpiece stored in advance.

By the way, the monochromatic light used as a light source is preferable because LED and LD which have a peak wavelength in wavelength 660-1550 nm are easy to obtain, a lifetime is long, and performance is stable. In particular, LED, LD light sources, such as 660, 670, 780, 800, 850, 1030, 1300, 1550 nm, are preferable. In light sources with wavelengths other than the above ranges, while the weight reduction rate of the workpiece is relatively small, the detector (receiver) may be overranged and may become impossible to meter. When the measured object is originally an acrylic resin, a polycarbonate resin, mineral oil, etc. with high transparency, light of wavelengths, such as 660, 670, 780, 800, 850 nm, is used. On the other hand, for opaque resins containing alkyd resins, unsaturated polyester resins, or epoxy resins that are quickly discolored, pigments, etc., in which the measurement object is originally colored, such as 780, 800, 850, 1030, 1300, 1550 nm, etc. Light of a wavelength in the near infrared region is used.

In the present invention, the irradiation optical fiber and the light receiving optical fiber do not need to be embedded in the device in advance, and since these optical fibers are not particularly required for their own heat resistance, use of a large-diameter plastic optical fiber as an optical fiber is avoided. It becomes possible, and light reception ability is improved and is advantageous.

The relationship between the weight loss rate of the measured object and the reflected absorbance difference between the respective wavelengths or the weight loss ratio of the measured object and the light transmission loss is obtained by an accelerated deterioration test performed by model. The relationship diagram obtained is generally called a diagnostic master curve, and a representative example is shown in FIGS. 3 and 4. This accelerated deterioration test is not particularly limited and can be carried out using conventionally known techniques.

In general, the change in the reflected absorbance spectrum accompanying thermal degradation of the organic material is represented by the change as shown in FIG. 2. As shown in Fig. 2, the reflected absorbance on the short wavelength side of the visible region with the deterioration shows a significant increase, and thus, up to the life point of the device in the wavelength region of less than 660 nm due to the constraint on the measuring range of the detector (receiver). It becomes practically difficult to continuously measure the reflected absorbance of the material in use. The increase in the reflected absorbance at this short wavelength side is mainly due to the increase in the electron transition absorption loss due to the thermal oxidation deterioration reaction of the material. As the deterioration progresses, the reflected absorbance increases by the shorter wavelength side, so that the reflected absorbance difference ΔA _λ (= A _{λ 1} -A _{λ 2} ) between any two wavelengths increases equally. Here, lambda 1 &lt; For example, in Fig. 2, when the reflected absorbance difference ΔA _λ between the wavelength λ 1 (nm) and the wavelength λ 2 (nm) is set to α 1, α 2, and α 3 in order from a material having a high degree of deterioration, a relationship of α 1> α 2> α 3 is established. . The same can be said for the light transmission loss.

Moreover, as described in Unexamined-Japanese-Patent No. 3-226651, deterioration degree is represented by conversion time (theta). By representing the conversion time θ, even when materials having various thermal histories are equal, it means that the degree of deterioration is the same. The conversion time θ (h) is defined by equation (4).

Where E is the apparent activation energy of thermal degradation (J / mol), R is the gas constant (J / K / mol), T is the absolute temperature (K) of thermal degradation, and t is the degradation time (h). [Delta] E of resins or oils can be easily calculated by plotting the change in reflected absorbance difference or light transmission loss with respect to various degradation temperatures by Svante August Arrhenius.

In addition, the terms of the time corresponding to the remaining service life when the service life in terms of time at the point of the device with oil and the like can be placed over pre-determined by θ _0, θ in terms of time with the difference Δθ (= θ ₀ -θ) obtained from the measured It becomes a measure of deterioration degree determination. In other words, the remaining life Δθ (h) is expressed by equation (5).

If the operating temperature condition of the device after time t is determined from Equation 5, the time Δt (= t ₀ -t) of the remaining life can be obtained.

If the actual operation time of the device is known, it is also possible to substitute the value in t to estimate the average temperature T when using the device using Equation 4. This will be described through examples.

<Example>

Hereinafter, the present invention will be described in detail using examples.

(First embodiment)

The example which diagnoses the weight loss rate of the epoxy resin which adhere | attaches the rotor bar by measuring the surface of the rotor rotor 1 in FIG. 1 is shown. First, the reference light quantity for each wavelength of two light source LEDs 3 and 4 is measured. In this embodiment, 670 nm is used as λ1 and 1300 nm is used as λ2. Monochromatic light of the peak wavelength λ 1 generated from the light source LED 3 is irradiated onto the standard white plate from the probe 2 via the optical fiber 5 for irradiation via the photodetector 6. The standard white plate is not particularly limited, and it is sufficient for alumina oxide, white plain paper, and the like, and there is no problem even if a chrome plated metal plate or the like is used. The reflected light is transmitted to the light receiver (optical power meter) 8 via the light receiving optical fiber 7, and the reference light quantity I ₁ of the peak wavelength λ ₁ is measured and stored in the data processing unit (personal computer) 9. Similarly, the same operation is performed using the monochromatic light of peak wavelength [lambda] 2 generated from the light source LED 4, and the reference light quantity I2 of the peak wavelength [lambda] ₂ is memorize | stored in the data processing part (personal computer) 9. Next, the amount of reflected light on the surface of the rotor rotor 1 is measured. In the same manner as the reference light amount was measured, the surface of the rotary rotor 1 is irradiated using the monochromatic light from the light source LEDs 3 and 4, and the respective reflected light amounts I ₁ ′ and I ₂ ′ are measured. The data processing unit (personal computer) 9 calculates and stores the reflectance R _λ1 (= 100 × I ₁ '/ I ₁ ) at λ ₁ and the reflectance R _{λ 2} (= 100 × I ₂ ' / I ₂ ) at λ ₂ . In this way, the reflectances at the wavelengths lambda 1 and the wavelength lambda 2 are obtained. Therefore, the reflection absorbance difference ΔA _λ (= A _{λ 1} -A _{λ 2} ) between the two wavelengths is obtained by the data processing unit (personal computer) 9. In the data processing unit (personal computer) 9, the reflected absorbance difference corresponding to the weight loss ratio of the resin as shown in Fig. 4 is stored in advance as a master curve, and the stored function value is compared with the measured reflectance absorbance difference ΔA _λ . It calculates and the weight reduction rate of the rotor rotor 1 is determined, and it outputs as a measurement result to an external printer (not shown).

5 shows the results of measuring the reflected absorbance difference continuously from the intake side to the exhaust side of the three rotor rotors. Since the cooling effect is low on the exhaust side, it is understood that the reflected absorbance difference on the exhaust side is large in the rotor that has undergone deterioration. That is, it can be said from FIG. 4 that a weight reduction rate is larger than an intake side. In addition, since the apparent activation energy ΔE of the epoxy resin used and the operating time t of the three rotors are known, the average surface temperature at the time of use can be calculated using Equation 4. The calculation result is shown in FIG. As described above, the present invention can not only estimate the weight reduction rate of the resin, but also can estimate the average operating temperature of the device which has risen in use.

(2nd Example)

The example in which the weight loss rate of the lubricating oil is diagnosed non-destructively by metering the lubricating oil of the engine unit 10 of FIG. 6 using the flow cell 11 is shown. First, the amount of reference light of the light source LED 3 is measured in the same manner as in the first embodiment. In this example, 850 nm was used as λ1. Monochromatic light of peak wavelength [lambda] 1 generated from the light source LED 3 is transmitted to the light receiving optical fiber 7 via the two optical probes 2 which face each other and are installed to face each other via the optical fiber 5 for irradiation. The transmitted light is transmitted to the light receiver (optical power meter) 8, the reference light amount I ₁ of the peak wavelength λ1 is measured, and stored in the data processing unit (personal computer) 9. Next, the amount of transmitted light of the lubricating oil of the engine unit 10 is measured. The flow which becomes the optical path length t (mm, t = 1 in this embodiment) in the clearance gap of the probe 2 which opposely installed using the monochromatic light from the light source LED3 similarly to having measured the reference light quantity. Through the cell 11, the amount of transmitted light I ₁ ′ of the lubricating oil of the engine unit 10 is measured. The data processing unit (personal computer) 9 calculates and stores the absorbance A _λ (= -logI ₁ '/ I ₁ ) at _{λ 1} . In this way, the absorbance at the wavelength λ1 is obtained, so that the light transmission loss _Lλ (dB / mm) is obtained by the data processing unit (personal computer) 9 according to equation (3). In the data processing unit (personal computer) 9, the light transmission loss corresponding to the weight loss rate of the resin as shown in Fig. 3 is stored in advance as a master curve, and the stored function value and the actual light transmission loss value L _lambda are thus stored. The comparison calculation is performed from to determine the weight reduction rate of the lubricating oil of the engine unit 10, and output it as a measurement result to an external (not shown) printer or the like.

According to the present invention, it is possible to diagnose the non-destructive weight loss rate of the insulating material, the structural material, the lubricating oil, etc. used in the device without stopping the operation of the device in operation.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the nondestructive diagnosis example of the rotor rotor which concerns on 1st embodiment of this invention.

2 is an example of a change in reflected absorbance spectrum.

3 is an example of a diagnostic master curve showing the relationship between light transmission loss and weight loss rate.

4 is an example of a diagnostic master curve showing a relationship between a reflected absorbance difference and a weight loss ratio.

Fig. 5 is a diagram showing the measurement results of the average surface temperature and the reflected absorbance difference of the rotor rotor of the first embodiment of the present invention.

Fig. 6 is a diagram showing an example of nondestructive diagnosis of lubricating oil of the engine unit of the second embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: rotor rotor

2: probe

3: light source LED (λ1)

4: light source LED (λ2)

5: irradiation light fiber

6: optical coupler

7: light receiving optical fiber

8: Receiver (Optical Power Meter)

9: data processing unit (personal computer)

10: engine unit

11: lubricating oil flow cell

Claims (4)

In order to calculate an operating temperature of a device having a material whose reflection absorbance (A _λ ) of Equation 1 changes under heat, the device is operated for a predetermined time (t), and the peak wavelength is in the range of 660 nm or more and 1550 nm or less. Reflectance absorbance difference ΔA _λ between the two wavelengths of a material in which the reflected absorbance A _λ of Equation 1 is changed by using the light having two different wavelengths λ 1 and λ 2 (λ 1 < _λ 2) Is calculated by Equation (2), and the master curve showing the relationship between the reflected absorbance difference of the material held in advance and the deterioration degree expressed by the conversion time (θ) and the reflected absorbance difference ΔA _λ of the measured two wavelengths. A conversion time θ is calculated from the calculation time, and an average operating temperature T, which is a heat history during operation at the measurement site of the device, is calculated from the calculated conversion time θ and Equation 3, Equation 1 is A _λ = -log (R _λ / 100), where the reflectance of the measurement object at the wavelength λ (nm) as R _λ (%), Equation 2 is ΔA _λ = A _{λ 1} -A _{λ 2} (where _λ 1 < _λ 2), Equation 3 is T = ΔE / R (lnt-lnθ), where ΔE is the activation energy of the material, R is the gas constant, t is the operating time of the device, and θ is the master result from the calculation of ΔA _λ of the material. Non-destructive diagnostic method, characterized in that the conversion time obtained by using a curve. The method of claim 1, wherein the object is a rotating rotor. The non-destructive diagnostic method according to claim 1, wherein the diagnosis is performed on a plurality of different points of the object. The non-destructive diagnostic method according to claim 1, wherein the plurality of target articles are diagnosed.

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